Software-defined networking (SDN) is a network architecture for decoupling control from forwarding, and has features of centralized control and an open programmable interface, that is, a controller on a control plane can control a switch on a forwarding plane by using a network communications protocol, for example, by using a new network switch model that is put forward, namely, the OpenFlow protocol.
In the prior art, the controller may control an action of the switch on the forwarding plane by using the Openflow protocol. The Switch bears multiple flow tables of service logic, that is, the Switch uses a pipeline based on flow tables to process a data packet. Specifically, each flow table may include multiple flow entries, where the flow entries are used to bear basic processing logic of the Openflow protocol. When receiving a data packet, the Switch matches the flow entries one by one according to a preconfigured priority order by using match fields in the flow entries, and after a flow entry is matched successfully, executes executable instructions in the flow entry, where the instructions include, for example, an operation (Action) list, modifying metadata, and directing to a subsequent flow table. Because a data packet generally needs to undergo matching processing of multiple flow tables, after an input data packet successfully matches a flow entry in a flow table, executable instructions in the flow entry are executed, and then the Switch directs the data packet to a next flow table to continue processing.
However, a quantity of flow tables supported by the pipeline of the Switch and a scale of flow entries that can be processed by the Switch are limited in the prior art. Therefore, when an operator needs to perform capacity expansion in terms of functions or performance for a Switch disposed in a network node, due to a limitation of a hardware capability of the Switch, the operator can only replace a Switch in an existing network with a Switch having a larger capacity or supporting more flow tables. Therefore, costs of network capacity expansion are increased.